Overview
Stage | Production |
Mine Type | Underground |
Commodities |
|
Mining Method |
- Sequential grid mining
- Breast stoping with strike pillars
- Undefined backfill
|
Production Start | ... |
Mine Life | 2026 |
Kusasalethu is a mature, deep-level mine 90km west of Johannesburg. The mine comprises twin vertical and twin sub-vertical shaft systems and uses conventional mining methods in a sequential grid layout. It exploits the Ventersdorp Contact Reef as its primary orebody. Ore mined is treated at the Mponeng plant. |
Source:
p. 58,95
Kusasalethu is wholly-owned and operated by Harmony.
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Summary:
Kusasalethu is located on the north-western margin of the Archean Witwatersrand Basin, one of the prominent gold provinces in the world. There are seven gold-bearing conglomerates within the mining right area, of which only the Ventersdorp Contact Reef (VCR) is economically viable.
Kusasalethu is situated in the West Wits Basin and mines the Ventersdorp contact reef as its main orebody.
The Ventersdorp Contact Reef facies model at Kusasalethu is based on the paleotopographic or slope and terrace model. Nine facies types have been recognised at Kusasalethu – eight sedimentological and one structural. Four of the facies are thick, high-grade, geologically distinct reef terraces separated from one another by a thin low-grade slope reef.
The sand-filled channel is a thick low-grade facies. The Sandy Terrace Complex is found on the same elevation as the Terrace Complex but is essentially a pebbly quartzite with no grade. The Mondeor conglomerates have been identified sub-cropping against the Ventersdorp Contact Reef in stopes in certain areas and have been delineated as separate facies in these areas.
The Elsburg conglomerates, found on the western side of Kusasalethu, form the footwall to the Ventersdorp Contact Reef and are part of the Turffontein Supergroup. It is a predominantly polymictic matrix-supported conglomerate of well-packed and moderately sorted, sub-rounded smoky (80%), black-grey (15%) quartz pebbles, chert (3%) and some ........
Mining Methods
- Sequential grid mining
- Breast stoping with strike pillars
- Undefined backfill
Summary:
Kusasalethu is a deep level underground gold mine, currently operating at depths ranging between 2,900m and 3,300m BMD. Access to the orebody is gained through a twin shaft system from surface to 73 level. The twin sub shaft system extends from 73 level to 115 level.
The VCR horizon is extracted at Kusasalethu, and mining is conducted over five levels (98 level to 113 level) using SGM techniques.
Due to the current mining depths at Kusasalethu, the SGM method with backfill and pre-conditioning is used. The SGM method is preferred due to the variability of the VCR orebody with respect to value, and the seismic risk associated with deep level mining. The mining sequence used for breast mining is a V-shaped configuration, colloquially referred to as the “inverted Christmas tree”. An underhand face configuration is adopted when mining towards the west, and an overhand face configuration when mining towards the east. The SGM method makes use of dip pillars and reduced mining spans with pre-developed tunnels, aimed at further control of stresses experienced during rock movement.
Primary development is done off-reef (in waste rock), while secondary development is done on-reef (in the mineralized zone).
Mining Operations The VCR horizon is extracted at Kusasalethu, and mining is conducted over five levels (98 level to 113 level) using sequential grid mining techniques. The ore mined at Kusasalethu is processed at Mponeng Gold Plant. The Kus ........
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Flow Sheet:
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Reserves at June 30, 2023:
Mineral Reserves are reported using a cut-off grade of 1,100cmg/t determined using a gold price of US$1,582/oz gold.
The Mineral Resources are reported using a cut-off value of 1,085cmg/t determined at a 90% profit guidance, and a gold price of US$1,764/oz.
Mineral Resources are reported inclusive of Mineral Reserves.
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven
|
1.7 Mt
|
Gold
|
7.44 g/t
|
402 koz
|
Probable
|
0.1 Mt
|
Gold
|
5.04 g/t
|
10 koz
|
Proven & Probable
|
1.7 Mt
|
Gold
|
7.36 g/t
|
412 koz
|
Measured
|
1.6 Mt
|
Gold
|
13.5 g/t
|
698 koz
|
Indicated
|
6.5 Mt
|
Gold
|
10.08 g/t
|
2,110 koz
|
Inferred
|
2.5 Mt
|
Gold
|
8.85 g/t
|
698 koz
|
Total Resource
|
10.6 Mt
|
Gold
|
10.32 g/t
|
3,506 koz
|
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